The present invention relates to a BTU meter (Watt or Joule) for thermal energy collecting and absorbing devices, particularly for solar radiation collectors.
Utilization of solar energy has become increasingly of interest due to the problems raised by fossil fuel; the problems are, of course, diminishing supply and pollution. Basically, two approaches have been followed for collecting solar energy. In one of these approaches, solar radiation is collected over a large area and in the order of megawatts to be stored and fed to a power plant, hopefully to satisfy the power requirements of an entire city. The other approach operates on a much smaller scale; each solar collecting unit collects and provides as much energy for use in the home as possible and as can be collected, for example, on the roof of the house. In order to induce consumers, for example homeowners, to use such a device, various incentives have been introduced such as tax relief or a lease arrangement. The lease fee is for example based on the consumption of energy and power but at a lower rate than it would cost the homeowner to electrically heat his house or to use gas or oil heat. There is, therefore, a need for an efficient BTU meter for such a solar heating system in order to determine the extent of the actual use thereof.